new file: platform_packages_apps_music-master/res/layout-keysexposed/create_playlist.xml

Author: hackboy

adapter/Adapter.java

@@ -0,0 +1,58 @@
+/**
+ * Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.widget;
+
+import android.database.DataSetObserver;
+import android.view.View;
+import android.view.ViewGroup;
+
+/***
+ * 一个适配器是数据和适配器视图的桥梁，适配器提供访问数据项的能力，并且为每条数据指定视图
+ */
+//好好学习这种模式，同时好好学习接口的用法等,这是什么模式呢，包含了好几种吧？？但真心不像是适配器模式
+public interface Adapter {
+    
+    void registerDataSetObserver(DataSetObserver observer);
+
+    void unregisterDataSetObserver(DataSetObserver observer);
+
+    int getCount();   
+    
+
+    Object getItem(int position);
+    
+    long getItemId(int position);
+    
+    //有何用处
+    boolean hasStableIds();
+    
+    //可以进一步优化吧
+    View getView(int position, View convertView, ViewGroup parent);
+
+    //这个是一种view类型
+    static final int IGNORE_ITEM_VIEW_TYPE = AdapterView.ITEM_VIEW_TYPE_IGNORE;
+    
+    int getItemViewType(int position);
+    
+    int getViewTypeCount();
+    
+    static final int NO_SELECTION = Integer.MIN_VALUE;
+ 
+     boolean isEmpty();
+}
+
+